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1. You'll need the remote control unit for any household gizmo (television, DVD player, stereo, air conditioner, whatever) and a digital camera with an LCD display (mobile phone cameras will do nicely).

2. First, push any button on your remote and look carefully to see if you can spot anything going onů you won't.

3. Now point the remote control unit directly into your camera's lens and watch the display while pressing that button again.

4. This time, you'll see a little white light rapidly flashing on your remote. Stop pressing and the light stops flashing. Your camera's 'eye' can 'see' the remote control unit's infrared signal and the screen converts this invisible chatter to visible white light. I shot the video clip above on top of my fridge with my mobile phone and television remote.

What's going on?

The remote control units in your house use infrared light to transmit your ever-changing desires to a small detector on their corresponding gizmo. Human eyes can't see this infrared light so, for the uninitiated, this can all appear rather magical.

A remote's flashing infrared signal is a bit like Morse code. Each gizmo in your house speaks a different 'language' that prevents the television doing strange things when you use the DVD's remote. Different manufacturers use different codes, which is why your old remote won't work on your brand new plasma. Even different models from the same manufacturer will speak a different 'language' to avoid unwanted chit-chats between your various appliances.

To successfully send its signal, your remote needs a direct line of sight between its light emitting diode (LED) and the detector on your gadget. If the angles are right, reflections from mirrors, windows or glass photo frames can bounce this light to your appliance too. So, if you're feeling bored, you could strategically position some photo frames or mirrors and secretly change channels from the bathroom to spook your family out (or at least annoy them slightly).

But why can you see this invisible infrared light through your digital camera's eyes? Well, you can't really. Human eyeballs cannot see infrared light no matter how hard you might like to try. Your camera's light detectors, however, really are sensitive to infrared light. The camera's internal circuitry sends the infrared signals that its detectors 'see' to the liquid crystal display (LCD), which then emits them as visible light that your eyes can, and do, see.